Walter Rheiner (1895–1925) was a German poet and prose writer associated with the Expressionist literary movement. Born Walter Heinrich Schnierer in Cologne, he is best known for his vivid depictions of urban alienation and the psychological effects of drug addiction during the early 20th century.
Rheiner’s most influential work is the 1918 novella Kokain (Cocaine). The text is regarded as a seminal example of Expressionist prose, utilizing fragmented syntax and hallucinatory imagery to describe the physical and mental deterioration of its protagonist. The novella is widely considered to be semi-autobiographical, reflecting Rheiner’s own long-standing struggle with substance abuse.
In addition to his prose, Rheiner published poetry and essays in prominent Expressionist periodicals such as Der Sturm and Die Aktion. His work often explored themes of existential despair, social isolation, and the disintegration of the self within the modern metropolis. His writing style was characterized by the intense emotionality and rejection of traditional realism common to his contemporaries in the German avant-garde.
Rheiner’s personal life was marked by financial instability and severe addiction to cocaine and morphine. He spent much of his later years living in poverty in Berlin. Walter Rheiner died by suicide in June 1925 following a morphine overdose. His literary contributions are primarily studied within the context of late Expressionism and the "lost generation" of German writers between the World Wars.